Persistent Trigeminal Artery Complicating Craniofacial Resection

Introduction: The trigeminal artery is a normal fetal structure that arises from the internal carotid artery and supplies the posterior circulation. It typically regresses and obliterates at the 6-mm embryo stage once the posterior communicating artery develops and establishes a connection between the distal internal carotid artery and the longitudinal neural arteries. In select cases, the trigeminal artery persists and the posterior intracranial circulation receives its blood supply via the internal carotid artery. The reported incidence of a persistent trigeminal artery is 0.2%; however, because there are unreported and undiagnosed cases, the actual incidence is most likely closer to 1%. We report a case of a persistent trigeminal artery complicating a craniofacial resection.

Methods: Case report.

Results: A 61-year-old woman presented with a right parotid mass. Due to the potential resection of the carotid artery at surgery, preoperative cerebral angiogram with Wada testing was performed. Angiogram showed the existence of a persistent trigeminal artery. The pathognomonic “tau sign” was identified and clearly showed the connection originating from the internal carotid artery (at the level of exit from the carotid canal) and travelling posteriorly to fill the basilar artery and supply the brainstem. Due to this anatomical variant, sacrificing the carotid artery was not a surgical option. The patient subsequently underwent a gross total tumor resection. Intraoperative margins in the region of the carotid sheath were negative. Pathologic diagnosis was acinic cell carcinoma.

Conclusions: Preoperative imaging to define the cerebral vasculature is imperative prior to craniofacial resections in the region of the internal carotid artery. In cases of a persistent trigeminal artery, internal carotid artery sacrifice may not be a feasible strategy.